: new construction: i am installing a one piece shower enclousure , with cement support, the floor is 1" and the joist are 2 x8 (full demension) spaced 12" do i need any extra support?

Shower enclosure with cement support such as a cement (concrete 48 inch square 3 inch thick) base? or what other kind of cement support? Is this a basement or single floor or is this on a second or third floor? What is the actual span of the 2x8 joists and are there any knots in the joists? If your enclosed shower dam is more than 3 inches full capacity, what will the total combined weight of the trapped water (if the drain backs up), the person (or two) inside the shower, the shower enclosure itself, and the cement support be? Those combined weight figures determine how much weight will be supported by the joists, but the SPAN determines if you need additional support. New construction? What do the specs call for?